How many units is 1 mg of PT-141?

It depends entirely on how much water you added. In a 10 mg vial reconstituted with 2 mL, the concentration is 5 mg/mL, so 1 mg is 0.2 mL, which is 20 units on a U-100 insulin syringe. In the same vial with 1 mL of water it is 10 units, and with 3 mL it is 30 units.

How much bacteriostatic water for a 10 mg PT-141 vial?

2 mL is the usual choice. It gives 5 mg/mL, which puts the commonly reported range of 0.5 mg to 2 mg between roughly 10 and 40 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.

How many doses are in a 10 mg vial?

Divide 10 by your dose. At 1 mg that is 10 doses.

How many units is 1 mg of PT-141?

In a 10 mg vial with 2 mL of water, 20 units on a U-100 syringe. The licensed 1.75 mg dose is 35 units at that concentration.

How long before does PT-141 need to be taken?

The licensed product is taken at least 45 minutes before. Reports commonly describe one to two hours. The half-life is about 2.7 hours.

PT-141 dosage calculator

PT-141 is dosed as needed rather than daily, usually 0.5 to 2 mg an hour or two beforehand. Enter your vial, water and dose to get the syringe mark.

IndependentThis site does not sell peptides and is not owned by a vendor. Every other calculator on page one of Google belongs to a shop.

The maths is openThe formula is written out on this page and the code behind it is a single file with an automated test suite.

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ReviewedDose ranges and half-life figures last checked 3 September 2026.

Dose to units, at the standard setup

Dose	Draw	U-100 units	Doses per vial	Vial lasts
0.5 mg	0.1 mL	10 units	20	20 uses
0.75 mg	0.15 mL	15 units	13	13 uses
1 mg	0.2 mL	20 units	10	10 uses
1.5 mg	0.3 mL	30 units	6	6 uses
1.75 mg	0.35 mL	35 units	5	5 uses
2 mg	0.4 mL	40 units	5	5 uses

Based on a 10 mg vial reconstituted with 2 mL of bacteriostatic water, which is 5 mg/mL, drawn on a standard U-100 insulin syringe, as needed (assume weekly).

About the numbers above

PT-141 is bremelanotide, a melanocortin receptor agonist. It is a licensed medicine (Vyleesi) at 1.75 mg by subcutaneous autoinjector for hypoactive sexual desire disorder in premenopausal women, with a limit of one dose in 24 hours and eight a month. Research vials of 10 mg are sold outside that licence, for both sexes.

A 10 mg vial with 2 mL of water is 5 mg/mL, so 1 mg is 0.2 mL, or 20 units, and the licensed 1.75 mg is 35 units. Nausea is the most reported side effect and scales with dose, which is why most people who use it start at the low end. It raises blood pressure transiently; the licence excludes people with uncontrolled hypertension.

A 10 mg vial at different water volumes

If the draw feels awkward to read, change the water rather than the dose. The dose stays the same; only the mark moves.

Vial	BAC water	Concentration	Draw	U-100 units	Doses/vial
10 mg	1 mL	10 mg/mL	0.1 mL	10 units	10
10 mg	2 mL	5 mg/mL	0.2 mL	20 units	10
10 mg	3 mL	3.33 mg/mL	0.3 mL	30 units	10

All rows above assume a 1 mg dose and a standard U-100 insulin syringe, where 100 units = 1 mL.

How long it stays in you

The half-life of PT-141 is about 2.7 hours. That is the time for the amount in your blood to halve, so after one half-life you are at 50 percent of the peak, after two you are at 25 percent, and after four you are at roughly 6 percent. It is cleared the same day, so there is no build-up between uses and nothing left over by the next one; the effect window is a few hours after each dose.

Common questions

How many units is 1 mg of PT-141?: It depends entirely on how much water you added. In a 10 mg vial reconstituted with 2 mL, the concentration is 5 mg/mL, so 1 mg is 0.2 mL, which is 20 units on a U-100 insulin syringe. In the same vial with 1 mL of water it is 10 units, and with 3 mL it is 30 units.
How much bacteriostatic water for a 10 mg PT-141 vial?: 2 mL is the usual choice. It gives 5 mg/mL, which puts the commonly reported range of 0.5 mg to 2 mg between roughly 10 and 40 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.
How many doses are in a 10 mg vial?: Divide 10 by your dose. At 1 mg that is 10 doses.
How many units is 1 mg of PT-141?: In a 10 mg vial with 2 mL of water, 20 units on a U-100 syringe. The licensed 1.75 mg dose is 35 units at that concentration.
How long before does PT-141 need to be taken?: The licensed product is taken at least 45 minutes before. Reports commonly describe one to two hours. The half-life is about 2.7 hours.

Buying PT-141? The where to buy page lists the vendors this site uses and what to check before ordering, and Peptide Bureau keeps the ranked vendor scorecard.

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Read this before you use the numbers. This is a unit-conversion tool. It converts a vial strength and a volume of bacteriostatic water into a concentration, a draw volume and a mark on an insulin syringe. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most of the compounds listed here are sold for laboratory research use and are not approved for human use. Nothing on this site is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always confirm the strength printed on your own vial rather than trusting a preset.